<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>04_原型链_属性问题</title>
</head>
<body>
<!--
1. 读取对象的属性值时: 会自动到原型链中查找
2. 设置对象的属性值时: 不会查找原型链, 如果当前对象中没有此属性, 直接添加此属性并设置其值
3. 方法一般定义在原型中, 属性一般通过构造函数定义在对象本身上
-->
<script type="text/javascript">

  function Fn() {

  }
  Fn.prototype.a = 'xxx'
  var fn1 = new Fn()
  console.log(fn1.a, fn1)

  var fn2 = new Fn()
  fn2.a = 'yyy'
  console.log(fn1.a, fn2.a, fn2)

  function Person(name, age) {
    this.name = name
    this.age = age
  }
  Person.prototype.setName = function (name) {
    this.name = name
  }
  var p1 = new Person('Tom', 12)
  p1.setName('Bob')
  console.log(p1)

  var p2 = new Person('Jack', 12)
  p2.setName('Cat')
  console.log(p2)
  console.log(p1.__proto__===p2.__proto__) // true



</script>
</body>
</html>